1. Field of the Invention
The present invention generally relates to an image formation apparatus, an image formation process control method, and a recording medium; and especially relates to an image formation apparatus that detects toner concentration using a toner concentration detection sensor, a control method of controlling an image formation process of the image formation apparatus, and a recording medium for storing a computer program for a computer to read and execute for carrying out the control method.
2. Description of the Related Art
[Background Technique]
As image formation apparatuses and image formation process control methods of this kind, disclosures have been made by, e.g., Patent References 1 and 2. Patent Reference 1 attempts to acquire proper detection of “toner end” (a status where there is no more toner available) by avoiding incorrect detection of “toner end” by a toner concentration sensor formed at the bottom of a development unit. According to Patent Reference 1, “toner end” is started to be detected by the toner concentration sensor when an accumulated toner supply time (that corresponds to an accumulated consumption amount of the toner) of the toner sent to the development unit reaches a predetermined value, wherein the predetermined value is defined by an estimated minimum accumulated time from the first use of a toner bottle (cartridge) to “toner end”. There, the predetermined value is stored in a nonvolatile storage that is arranged at the bottle in one body. Further, every time image formation is carried out, the accumulated toner supply time is updated and stored for each toner bottle. In this way, the start time of detecting “toner end” is properly determined.
According to Patent Reference 2, no special sensors are used, but a period during which the toner is actually consumed is used as representing toner consumption from the toner bottle. Here, in an attempt to reduce estimating errors with reference to actual toner consumption, a nonvolatile storage is provided on the toner bottle for storing information on the quantity of toner consumed from the toner bottle. The nonvolatile storage is exposed on the top face of the toner bottle, and is connected to a control unit of the main body of the image formation apparatus through a contact terminal on a fixing member of the toner bottle. There, the residual quantity of the toner in the toner bottle is calculated based on the toner bottle capacity, a supply capacity (for example, 0.5 g/s) of a powder pump for toner supplied from the bottle, and toner supply time. In this way, the error with reference to actual toner consumption is minimized.
[Patent Reference 1] JPA 2002-258596
[Patent reference 2] JPA 2002-341640